Instagram seems to be fully aware of the potential backlash to come with ad integration, so they're easing users in as slowly as possible. A few weeks ago we were told that ads were coming, and now, users in the United States actually get to see them in the proverbial flesh.
The photo you see above is Instagram's own specially made ad meant to give you a taste of what's to come. Instead of a timestamp in the upper righthand corner, you'll be seeing the actually fairly noticeable word "Sponsored." With so many advertisers trying to make their content blend in as much as possible with the users' own, it's at least nice to see that we shouldn't have too much of a problem skipping over the ads as we're browsing our feed.
But if you do choose to stop and stare, you can hit the "..." button and let Instagram know whether you enjoyed your sepia-toned ad for laundry detergent. They'll then, presumably, tailor ads to fit your interests the more you rate them. Is it a little annoying? Sure. But that's the price you pay for paying absolutely nothing at all. [Instagram]