Sightings of the Twitter "fail whale" — the iconic graphic that indicates the site is not working — have been so common that #failwhale and #whiletwitterwasdown were among the top trending topics this week, reports the Los Angeles Times. Twitter communications chief Sean Garrett acknowledges that June has been its worst month since last October, when the service was down for more than five hours, and he says to expect "rocky few weeks" ahead. Here are four possible reasons why:

1. World Cup mania is swamping Twitter's servers
The microblogging giant thought it was prepared for "heavy traffic during World Cup matches," says Jennifer Valentino-DeVries in The Wall Street Journal, but clearly it wasn't. If the site can't ensure stability for predictable spikes in traffic, how can it sell "promoted tweets" to advertisers?

2. Introduction of "Twitter Places" overwhelmed the service
At least one of the big recent outages is directly linked to software tinkering related to its new Foursquare-like location feature, Twitter Places, says Nick Bilton in The New York Times. Given World Cup fever, execs probably picked a bad time to roll out the service, but as Twitter co-founder Biz Stone has noted, "expanding Twitter is like building a rocket ship in midflight."

3. Blame Lady Gaga
"Lady Gaga’s massive stardom" — specifically the debut of her video "Alejandro" — crushed her site first, then Gaga Daily, then Twitter, says Susan S. at Gather. At least that's what I learned on Twitter. And I believe it. Everything Lady Gaga does, she does big, even when it comes to bringing out the fail whale.

4. Twitter can't handle its rapid growth, period
The simplest explanation? Twitter just can't "handle its emerging status as the world’s real-time communications network," says Mathew Ingram at GigaOm. "This is not to beat up on the company" — it's trying to do something "incredibly ambitious" — but it should worry us. The service isn't "frivolous or useless," as emergency responders, Iranian protesters, Haiti earthquake rescuers, and others among Twitter's nearly 200 million users can attest. So perhaps its time to ask if Twitter needs help — or competition.