Stop Using the text-indent:-9999px CSS Trick

Notice that the linked google employee(http://maileohye.com/html-text-indent-not-messing-up-your-ra...) has no real solution. Everything is still in development. Though if your site layout is conducive Google's search results are a good alternative (They still don't use the alt property).

While the text-indent css is a hack. For now it is the best we have. The alt property will get you in the search index, it will not allow for good display when google returns a result. That little snippet of each site that google shows is hard to get right using just alt text.

We should be moving away from using it, however right now almost everyone uses it. Google won't penalize you for it yet.