Good points. The fact that you can only leave one single comment on an image prevents a true "discussion" in the comments section of an image. So that's not a real problem. And about database reservations/loads: it doesn't work that way. Databases (including MySQL) have fixed length text fields, variable length text fields, and Binary Larbe Objects (BLOBs).
Fixed length textfields behave like hawkfyr describes. They're useful for fixed length texts, like ZIP codes or telephone numbers. Variable length text fields: actual storage and load consists of the actual text length itself plus a two-byte number representing the length. Useful for names, addresses, short commentaries. And BLOBs only reserve a 16 byte pointer in the record itself, pointing to the actual location of the data (which can be VERY large, more than 1 GB per data item - depending on the database engine). BLOBs can contain complete novels, graphic images, movies, complete programs, just about anything. The maximum size of a comment (and IM, and forum post) makes me think that Bondware/MySQL uses variable length text fields for these features. So memory reservations and record size will be dependent on the actual content. Unless the current Bondware 2.0 is designed even worse than we already know...

The pen is mightier than the sword. But if you literally want to have some impact, use a typewriter

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