What was the reason given? To save cost on domains?

KubuntuGuide underwent a style revision to make it load faster, use icons better (to make it more tablet/netbook friendly), and to translate more easily into other languages. Also, it was organised so that it could easily be converted into eBooks ( .epub and .pdf formats ).

When this was accomplished, it was decided to do the same thing for UbuntuGuide, and then it became an obvious no-brainer to merge the two sites (since the formats ended up being so similar). Also, the host computer serving UbuntuGuide.org resides at the University of Latvia, which uses a cached proxy to improve loading speed and which has nearly 100% availability and good bandwidth. While their servers are not perfect (their Squid proxy could use some tuning up, IMO), it suits the purpose well.

KubuntuGuide never used ads, and there were old complaints about UbuntuGuide and its obtrusive display of ads, but that has been changed (with the minimal ads moved to an unobtrusive sidebar location ).

Domain names are only $10 per year; that's not a very big expense. However, the UbuntuGuide.org domain name has been in use for a very long time and has always ranked pretty well (and that is a benefit). In contrast, KubuntuGuide.org and KubuntuGuide.info refused to use Google Analytics (to their detriment) and therefore never ranked very highly.

Full details are at (K)UbuntuGuide:

http://ubuntuguide.org/wiki/Current_events