The New Zealand based site supports around 100,000 Swickis (a service of that lets the site owners highlight other sites to be added to Swicki search results).
According to ReadWriteWeb, a blog entry from eurekster stated that:
"We’re happy to let you know that our service has been fully restored and all your swickis should be back up and running again."
Although they’ve mentioned their comeback yet the reason for breakdown remains classified. Furthermore they have launched the full version of eurekster. I think they have done so in order to hide out the actual reason of their unavailability.
Anyway whatever the reason may be, the thing is that they are back in business which is certainly going to please their fans.