Blogulate

Service Temporarily Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.
Apache/1.3.33 Server at blogulate.com Port 80

This message was plaguing blogulate two days back. Although it’s gone now, I was unsure what was happening as blogulate hardly even reached 10% of the 1500GB monthly bandwidth.
Curious to know what was happening, I mailed the Customer Support. This was their reply:

Thank you for contacting Online Support. Unfortunately I am unable to duplicate the issue you are reporting. Based on the error, the problem may be related to the number of visitors on the site. A maximum of 50 connections can be supported on Linux hosting accounts. If that amount is exceeded you may receive such an error. Unfortunately the only way to alleviate such a problem is with a dedicated or virtual dedicated server.

Please let us know if we can help you in any other way.

It seems that GoDaddy’s max. number of simultaneous connections at any time is 50 for the Linux Hosting account.
This is sort of bad as most browsers use pipelined simultaneous requests and 10 users accessing your site can easily take 50 simultaneous connections.
It would have been been better if the 51th connection wait for a connection to terminate and then connect. However, the visitor just gets a 503 Error message. If it is a visitor making his way to your site from a Search Engine, it would appear to him as if the site was down as the bandwidth had exceeded and he’d just go away w.o retrying.
However, blogulate.com has had the same amount of traffic for the past 2 days and the error never re-occurred.

Here are links to more resources on the topic
The Service Temporarily Unavailable Error on Godaddy Hosting

Godaddy 503 Error : DP Forums

Godaddy 305 error @Webhostingtalk forum