Weebly is becoming a proof of concept. That you can withstand pressures of companies like Google when you outperform their own similar products.
I just can't see how Weebly can win. In theory they could get so much better than Google that Google (or Yahoo or Microsoft) buys them because of their loyal user base and better product. This is pretty much the Youtube story, but Youtube at least had the potential to monetize without Google, which is not the case with Weebly.
I do think they are a nice acquisition target for Yahoo or Microsoft, though - both having their own ad networks and no similar offering, it makes a lot of sense for them to buy Weebly and integrate it with their advertising platforms.