Ask HN: Mobile-friendly version of mouseover?

There's a lot of cool stuff I'd like to do on my site with mouseover effects. Mouseover a character and get a longer description. Mouseover a control and get a tooltip. All that kind of jazz.

However, more and more of my users are using mobile browsers like iPhones that don't really have a concept of mouseover.

How are other people dealing with this? Do you add the mouseover effect anyway, knowing that mobile users will never use it (and probably never know it exists), or use another control?