I suppose it could be an indicator of your motivation. If you're making 80k and are looking to be paid at least 70k, it might show that at your level, you could potentially get 90k if you wanted, but have other considerations than money.

The site's called "job poacher". You poach a good dev (who likes his job) by offering significantly more money than they're making now. 15k-20k more is usually enough to snatch anyone from anywhere.

That's assuming the numbers they disclose are even honest to begin with.

I agree, I've never understood why that data point is relevant to the job I'm applying/being-recruited for.

I think it's even more interesting when the first number is more than the second, as it is in the listing below:

"I'm a Mobile Product Support Specialist, and I currently make $90,000 in Mountain View, CA. I'm ONLY interested in jobs as a Community Manager, Product Quality Analyst, Junior UX/Interaction Designer that pay at least $65,000 in San Francisco, CA."

I assumed it is by people who want to jump-start a new career path, eg: from developer to designer, or want to move to a different city.

Because they want to offer just enough for the money to be attractive to you, but no more.

But that only explains it from the poacher's perspective. The question still remains, why would the poachee want to state their current salary?

They don't know how to negotiate