[tejaswiy]

An incredibly huge one. If they've found microbal life reasonably close by, then atleast on a personal level, I'd think the possibility of intelligent extraterrestial life can be taken MUCH more seriously.

That said, I'd think it'll be much less spectacular, possibly yet another condition added to the pre-requisites required for life.

[itistoday]

Considering your existence, that possibility should already be taken seriously.

What's interesting though, is that if they actually find evidence for microbial life on another planet far away, then it's mighty likely that said planet already has far more complex life on it (taking into account the time it takes for light to travel through space, we'd be viewing outdated information).

[aperiodic]

Ever heard of anthropic bias?

The question is not whether it's possible, but whether it's common.