Usually that's what happens for most of the bigger online forums..
If you care to read my thoughts of the logic behind it all:
A new dude/dudette appears from a search engine on something or stumbled on a link, then when they arrive and stand in front of the alldeaf directory it splits into the type of person they are before they post.
A true lurker doesn't post but reads as much as they need to know: Sometimes they'll register and never make a post, just to be able to search the forums to bypass the headache of the captcha image.
A curious one looks around a little, has a really interesting question or wants to know more about the forum/basis of it and their questions provoke or gather a lot of interest of the mainstreamed forumers. A lot of this "Breed" disappear after asking something.
A "gossipy one" or I dunno how to give a terminology for it; is what I consider registers, reads stuff and posts a ton within the hour they have registered.
There are also subdivisions of the three above to me, and the individual are then varied by type (examples like troller/flamer, lurker variations, stuff like that just like in society having KKK members, NRA group, etc)
The dedication of these individuals is then another story. But honestly I think from my own opinion the ratio of those who "post and run" versus the ratio of those who make their new+introductory post is higher as if something is influencing people to go.
The following is just a wild shot hypothesis:
I would suppose the average hearing person has less attention span versus a deaf person. On the forum we expect timely replies much due to the fact that we recognize that this is a form of communication that is in our favor. The average hearing probably does not care much for "keeping in contact", as they have their means and reasons not to do so.
Thus we are more prone to recognize "post and run" than they care to give two cents about it.
Other random stats if you care to enjoy my math as I did:
25,150 total members.
Guesswork:
~30 unique active members posting per day: random figure.
~100 unique posting members per week: a little high, but being optimistic.
~400 unique members posting per month (this includes the two above)
~500 unique visitors per day. (Based on Last 24 Hours data, includes guests, bots, clones, banned, etc)
~1000 uniques per week: random figure)
~1500 registrants (including spam, clones, everything) every six months = 250 per month.
Following numbers a bit off, but probably not too far from the real one:
• 60-70 "Hi" threads from the month of march '09: mean = 65
• 184-200 "Hi" threads from month of jan '09 to end of march'09: mean = 192 • 64/month
= averaging this out per month from above two data: 64.5 average new posters per month.
Guesswork statistics for jan09-mar09:
• 00.4% of all registered members post frequently/weekly.
• 00.2% of all registered members post daily.
• 01.6% of all registered members post monthly.
• 06.0% of daily visitors post. (~94% are doing other stuff, but a good chunk of this is crawling bots, like I'd say anywhere from 40-60%)
• 10.0% of weekly visitors post.
• Not sure of monthly data, but I would randomly guess this is around ~15% of monthly visitors post.
• +06.0% to population every half year, safe to guess around ~ +1.0% /year at this rate.
• 25% of all new registrants make one post.
I assume 3 out of 4 people disappear after posting:
• 6.5% of all new registrants participate after making their first post.
I don't have data from '08 and years before, never bothered doing simple statistics but it would be nice to compare it now.