I just finished backing up my GMail. It took several days for two reasons:
1. I have more emails than I was lead to believe. Google listed 48K emails, but it really meant 48K conversations. That actually amounts to 84,000 emails. That is nearly double and puts my average over 40 emails a day. That is not high, but combined with my active RSS feeds, that's a lot of input in each and every day.
2. The mail program I used (Mozilla Thunderbird) didn't want to download all the messages at once. It did 500 at a time every minute for a few days and then hit 70 and then 20 messages at a time when we neared the present. I dont really understand.
The last number you see in the chart is the annualized total of emails. We're 195 days into 2011 and I got 14,444 emails. That translates into 27K for the year, but because the slope of email appears to be rising, the final total is likely to be higher.
I have to admit, these numbers seem huge to me. Imagine what you can do if you put a small effort into this pile. Say, email you friends once a week. Call it 5 friends * 52 weeks = 260 emails. Even if the pile of email I get requires no response, I am still left asking, "Why don't I commit 1/10 of 1% of my email box to people I love?" And that is how all that data can lead to guilt. You're welcome.