He had a brief stint as co-founder of fitness app Chorus, which he quickly shuttered after it failed to catch on. And now, he’s focused on investing in and advising a few companies that he says have similar growth challenges as Twitter (TWTR) did before its initial public offering.

His latest investment, announced exclusively to Fortune, is in fast-rising business software startup Airtable. The company specializes in software tools that let people who aren’t coding geniuses create apps for their businesses to use internally, pitting it against giant tech companies like Google (GOOG) and Microsoft (MSFT) that sell similar products.

Customers include Netflix (NFLX), Atlantic Records, and Condé Nast Entertainment.

Costolo plowed an undisclosed amount of money into the $7 million funding round, an extension of a previous $52 million round that the company closed in March. Other investors in the latest round include prominent business executives and philanthropists Marie-Josee and Henry Kravis, and former Twitter executives Katie Jacobs Stanton and Elad Gil.

Airtable was co-founded by Howie Liu, who previously sold his older enterprise software startup Etacts to Salesforce (CRM) in 2011. With the new funding, Airtable has raised a total of $70 million.

In this edited interview with Fortune, Costolo discusses why he’s investing in Airtable, his thoughts about Jack Dorsey taking over as Twitter’s CEO, and political discourse in the Donald Trump era.

Why are you investing in Airtable?

Even though there are a lot of companies in the SaaS [tech jargon for cloud-based business software] space for collaborative work, I thought that Airtable really had the ability and the potential to do for software creation what the Macintosh did for personal computing.

If you think back to when we were all working with C:/ command prompts [reference to old-school computing programming] and with Microsoft operating systems back in the day, along came the Mac and just made PCs accessible to everyone.

You’re interested in the fact that Howie’s intent is to stick with the company and not eventually leave and be replaced by a more experienced CEO.

You’re exactly right. I’m 100% interested in working with founder/CEOs who have every intention of remaining a CEO, growing the business and sticking with it, and building something great.

What happens when there’s too much concentrated power within founder/CEOs and no one’s able to tell them what to do?

That’s a fair question. I think that there’s a difference between public company governance, where you’ve got everything from all the decision-making and voting rights and everything is consolidated to one-person—and there’s no other way around it. I think there’s a difference between that and a CEO who is growing a private company with less than 100 people, and is scaling the business.

You’ve been publicly supportive of the #MeToo movement. Many start-ups tend to focus on only their products and ignore important institutional values as they grow the business, which can lead to potential problems down the road.

I’m completely and 100% behind your hypothesis about how important that is. Between both Airtable and Patreon [the artist-centric crowdfunding company], where I’m on the board, the thing that you’ll find across all those companies is you’ve got CEOs who not only acknowledge how important that is, but put their money where their mouth is.

Howie’s going out of his way to make sure he’s got more women investors—Katie Stanton joining me as an investor. Howie spent a lot of time with Jenny Lefcourt on the Founders for Change, an initiative that she’s been part of putting together.

I’m in complete agreement with you that those institutional values, as you put it, are just as important as scaling the business, your business acumen, and your willingness to learn.

Since you’ve left Twitter, the company’s stock has gone up and there’s a perception that things are much better. How do you feel about Jack Dorsey’s recent tenure as CEO?

Listen, I was the one on CNBC saying Jack was doing a great job when the stock was at $15 [Twitter’s stock is now around $44]. Unlike all the other analysts who sold Twitter when the stock price was $15, I’ve been a fan of his ever since I’ve known him. Of course, all those same analysts are now talking about what a great job he’s doing, and recommending to buy those stocks, now that it’s expensive.

I don’t know how the guy is able to do such a great job of running two companies. I haven’t seen him this happy in a few years, so good for him.

You said that you regretted during your tenure not doing enough to police bad behavior on Twitter. How do you feel Twitter is doing in that area now, especially in this intense political environment?

I’ll say a couple things about this. One, I think our society in general right now, particularly in the U.S. across the media landscape is a little bit dysfunctional in the sense that people are just yelling at each other. On the one hand, you can’t expect the platforms to just correct that. You’ve got a president who calls people names, like a fourth grader, and you can’t expect the platform to stop this societal dysfunction.

On the other hand, all of these platforms need to, and I’m sure will, continue to invest heavily in dealing with this while also continuing to deal with things like spam, and then the new vector of meddling in politics. And it’s not just Twitter, it’s YouTube and Facebook, and others as well.

People argue about whether these platforms facilitate that discord or that they merely are reflections of the discord.

There’s for sure a part of this that’s a reflection of the discord. Again, you’ve got a president who’s modeling the behavior of calling people names. So, what do you want the platforms to do about that? There will be a piece of it that’s a reflection of what’s all in society.

I just think there’s a sense of, “Well, just delete their account if they do X, Y, Z.” But there might be times when people rightly raise their voice at other people. It may be a customer service complaint, or it may be a particularly hotly charged political issue like this separating children from their parents at the border. It’s a harder problem than the simple solutions that are suggested for it, but at the same time, these platforms all need to recognize, and they all do, that there’s a lot more work to be done.

Are you seeing more technology companies having to comment on political or controversial issues than they had to in the past because of this politicized environment?

It’s funny you say that. If you go back to end of 2010, when I first became CEO of Twitter, it was generally not the case that tech CEOs like myself thought of themselves in the context of their role in the geopolitical spectrum, or in society in the larger context. I remember getting a phone call on a Monday morning and it was the White House and I was like, why are they calling me? What’d I do? It was Valerie Jarrett, Obama’s chief of staff [Jarret was a senior advisor to President Obama] wanting to discuss some bigger geopolitical thing that was going on.

Now, I think some of these younger CEOs like Howie know that they have a role to play here, know they need to take leadership to this initiative, and know that it’s no longer even okay to just pay lip service to these things.

What was the bigger geopolitical thing you had to talk about?

if I remember correctly, it was during the Arab Spring when people were organizing protesting on social platforms like Twitter—starting with organizing protests in Tunisia. It was a conversation about what does it mean for the world and is there anything interesting we can do to be helpful to you guys as governments start to do things like shut down these platforms so people can’t organize protests. Not meddling, but just interested in having the conversation about what are you guys seeing, and what’s interesting that we’re seeing that’s not necessarily out there in the public, if you’re just looking at Twitter, et cetera.

Who was Twitter’s biggest competitor when you were there?

Facebook. We were always under the shadow of Facebook (FB). They have an enormous user base. We were both advertising based. We were both feed-based advertising products. I think it’s correct to say that they were originally advertising over on the side of the webpage, and then they migrated to that in-feed advertising format after we did. I think that’s correct, but I might be wrong about that. I’ll probably get yelled at by some of my Facebook friends.

They were just much, much bigger than us, so that’s always a tough position to be in, and you’re trying to find strategic beachheads to get out from under their shadow.

What were some things you learned from your stint as a consultant for Silicon Valley [The HBO satire of the tech industry]?

I came out of the Silicon Valley writer’s room experience realizing how hard it is to be a writer in Hollywood. You’re in the room for like 10 hours. You don’t leave. Coffee and lunch come in, but you’re writing the whole day. Then, someone’s got to take the script, go home, write the whole thing up and put it in the format. It’s not easily romanticized, like oh, what a fun, easy, creative job it would be. It’s creative, but it’s hard.

Is there any joke or premise from Silicon Valley that I could trace to you?

I had some input, things that got into the script, but sadly, none of the really good one-liners and jokes I can take credit for.