A commentary is a place where users can add their opinions on items, places, or decals.
The commentary was added since places were created by players in 2007, with the delay for commenting at the same place starting off at 15 seconds.
Rise of spam comments
By later years, the administrators of Roblox decided to limit players from continuously posting comments every second. This action to extend the delay was done to combat the prevailing spam comments that were continuously appearing on Roblox, which included those that claim about the ability of a user getting lifetime Builder's Club membership and/or infinite Robux by posting the spam on a certain amount of different items and those that include a potentially harmful link. From now on, the delay was extended to 3,600 seconds (or 1 hour).
Since its creation, users often posted comments about a different subject rather than the main topic of that commentary. Other players encouraged users to do what they ask, such as joining a group or sending a trade. Some players advertised to try and get attention. However, the majority of the commentary found in Roblox consisted of "spam", where players just post comments that is off-topic and has nothing to do with the subject at all.
As of May 2013, players are required to be verified in order to comment on assets.
When users commented on catalog items (including places, decals, models, etc.), a tiny yellow check mark might appear next to the time the comment was posted. This yellow check mark indicated that the user owns the item.
At one point during the Tixapalooza sale, comments began to be disabled on many gear items and some hats, potentially due to users repeatedly posting spam comments to try to get others to play their game, send trades, post links to scam websites, buy their clothes, etc. As of now, comments will be disabled for future catalog items because of this.
On May 18, 2016, comments were then disabled from all catalog items which were made by Roblox. This was due to a massive number of bots spamming links to scam websites. Similarly, comments were removed from all games on December 2 of that year, for the same reason. As of that date, comments cannot be re-enabled due to its configuration being hidden. However, shirts, T-shirts, pants, accessories, meshes, images, decals, models, plugins, and audio will still have comments enabled if the creator allows them.
Four weeks later on December 30, the tiny yellow check mark indicator was removed due to the massive UI overhaul that occurred since late 2014.
At 2018, Roblox disabled comments in badges due to a furious number of bots that spam the comments.
Spam is an infamous element in the comments, commonly posted by newer users, group owners/admins, users who want to get the Homestead or Bricksmith Roblox badges by advertising their place at the comments for other users to visit, and sometimes, hackers who post offsite links. However, offsite links are usually reported right away as the hacker can hijack the respective account that went to the link. Some users also attempt to perform an action called "Spam Clean" to get rid of spam by adding a large space in the comment, only resulting in a gap in the comments, thus, it counts as spam. Some users also post parodied spam that is against spam. However, the administrators are trying to protect comments from spam and crack down further on future spam. Unfortunately, many players now have verified e-mails and post spam, thus, the comments section of many items and places continue to contain spam to this day. Though the moderators are planning to add a spam flag action in the future, thus, many comments, regardless of whether or not they are actual spam comments, will also be flagged as spam by many users when it is implemented.
Recently, Roblox disallowed putting :'s in comments, it now simply displays an error when putting it in. It originally said that "Do not post links!", but this still happens even when the player did not post a link.
An example of a disallowed comment:
You can easily see the fact that the comment does not have a link, but there still is a :.