Suppose I wanted to post my 850,000,000 word epic poem in its unabridged form for fellow dopers to critique. Would I be able to do it? Is there a maximum number of characters that the software will allow in a single post?
I’m afraid the SDMB is not equipped for Ung poetry. You might try submitting it to Teemings, though.
Now in it’s sixth volume at** http://www.teemings.com/ **
Well, let’s put it this way… I’ve written some LO-O-O-O-O-O-O-O-ONG (like, “John Holmes” long) posts, and I’ve never gotten a “Yer friggin’ post is too durned long!”
I went poking around the vBulletin site and I found the answer. The maximum length of a single post is…(drumroll please)…
16,777,215 characters.
I am told that vBulletin uses a mySQL database backend and the posts are stored in a MEDIUMTEXT column (which is limited to 16 megabytes in size). Assuming an average word length of six characters (including the space), a single post can contain about 2,800,000 words. Just to put things in perspective, a typical novel runs about 90,000 words in length.
So it looks like my poem would be truncated right about where Zorthrox slays the giant wildebeest. Damm! That’s the best part.
You can always pull a Pink Floyd and do a “Part I” and “Part II” thing to it. 
Regardless of what MySQL allows, the vBulletin software assigns a limit, which can be adjusted by Tuba and/or Lynn as they see fit. I think the default limit is 20,000 characters (or it was in my version of MySQL) and that fits with my experience in making a long post or two here.
Also, I would not post original works here ever, for at least 7 good reasons. I would post them on your own website and provide a link. You may also note the text at the bottom of every page, which says:
I search these boards, by no means thoroughly I have to say, and come up with a post which meaures 3 feet 8 inches, from top to bottom, although what is the metric equivalent I do not care to calculate.
In the matter of length this is probably small potatoes, and many citizens will know of posts which exceed this distance, and maybe there is a post which approaches the world long jump record, for all I know, or maybe it is further.
That should read, “in my version of vBulletin”. :o
Hmm… 20,000 characters. That’s about 3,000 words – I think I’ve written papers in college that were longer than that. So I take it that any post longer than 20,000 characters will be truncated without warning?
On the new vBulletin it will warn you before truncating. On this version it will truncate on preview, and you can see how much it accepted, and then break your post up into better chunks. That is probably the best way to do it.