Last night my HTC Desire had a 'moment', showing 'low on space' messages and 'force close' errors. After some searching around the web, I found other people with the same problem: it seems there is a bug with either the Facebook Android app or the HTC People app which causes the 'contact storage' program to balloon in size, going up to 59mb on my phone. I tried uninstalling some apps, but the 'low on space' messages kept on popping up and, very quickly, the phone became unusable, constantly generating error messages.
I turned the phone off, but it then became trapped in a repeating sequence of getting to the boot screen and then restarting. There was nothing for it but a hard reset. Gulp.
Following the instructions on the HTC website, I hesitantly set about wiping and resetting the phone.
My HTC Desire booted up and, because of the magic of cloud computing, all I had to do was login to my Google account and all my contacts, calendar events and email were downloaded to my phone. No need to plug it into a computer, it's all done over the air. All of my photos, music and podcasts are on a separate SD card and were unaffected by the phone wipe and reset. However, all the apps I had downloaded and any customisations of ringtones or wallpapers, for example, were lost.
If the problem actually is with the Facebook contacts and HTC People app then there are several things you can do to avoid it. On the initial setup screens, do not choose to link your Facebook account. Also, do not link phone contacts to Facebook contacts in the HTC People app. When you add new contacts, make sure you add them as Gmail contacts, then they will be synced with the cloud and you can easily retrieve them if you ever need to do a factory reset again.