tl;dr: there are alternatives available now, and at least one more to be released soon - I know this because I'm working on one of them (hit up my DMs if you want a notification when it's released)

Basically YikYak failed because it isn't profitable. I'm sure they sell your data to various brokers but that alone usually can't pay the bills unless you're huge, and aside from that: shitty ads and swag simply don't justify the number of people they hired. The business was kicked off during a time when "not profitable and no idea how to become profitable" was not nearly the negative it really should be for prospective investors. With interest rates going up, however, suddenly everyone remembers the point of a business (and investing in a business) is to make money and YikYak never had a good plan on how to do that. So, they're not getting any more funding, they're out of runway, and they're done.

Regarding your data: the #1 rule of social media apps is that if you're not paying for the product, you are the product. I know at least one app releasing soon which is much like YikYak but it will never sell user data and it will never serve ads except maybe on the free tier (I think we're leaning toward not doing that, at least initially, but it's not decided yet). How is that possible? Well, simply put we don't intend to make our users the product - our users will be our customers and we will have a subscription model. Will it succeed? Don't know! It's very difficult to get users to pay for anything after all, especially on Android by the way, but I can tell you that we're firm on this business model and that we'll go out of business before we budge on the "no selling data" part of it.

Feel free to hit up my DMs if you're interested in a notification when we go live.