Ugh. I've just been mining in the BTC pool for the past 10 hours and I had the wrong username and password, over 5000 shares. I just changed my username in GUIminer. I don't suppose I'm going to get credit for the mining I've done all day, am I?

I was wondering why I couldn't post on this forum then read the newbie restrictions.

Well, I've been mining BTC since the summer of 2011. Back then, I was able to mine about .50BTC every other day (using Slush's pool). I quickly mined about 10 coins and then hung onto them until February 2012, when I sold them for about $10USD.

I was mining those on my mini-farm of a Radeon 4850 and 6950. The 4850 wasn't doing all that much, maybe 40MH/s. The 6950, about 310-325 MH/s.

I'm still using the 6950 and, have a question about difficulty. I have read some of the charts showing the exponentially rising difficulty in mining. It seems that on a pretty full day of mining (and using PC during working hours), I'm able to mine about .03BTC every other day. This is about 1/16th as much as I was mining in July 2011. Has the difficulty increased so much that this makes sense? It didn't appear to at first glance.

Any input would be greatly appreciated!