An alternative could be the edit option. If changes are made to threads, and the updates could get lost in the replies, the OP can edit the original topic, and bump up the thread so it increases visibility.
This quote from theymos suggests that he may not want to allow thread starters to have extra benefits:
The purposes of the unofficial rule are:
2. Prevent people from monopolizing pages of topics, which is unfair to other posters.
Well, bump is always an option to each thread. I mean if OP just comment in it then thread automatically comes up and users get directed to it.
But, over the time mega threads get fill up very fast and we literally have to go through each page and check the update. I mean by the time minute hand moves there would be 3-4 pages added already. The new reader will come and see people debating but has to go back and check what is it all about.
About the theymos rule, up button won't break it because it will be limited to the OP only and not everyone in that particular thread. If we are already given reserved option then by UP movement of later updates would be same thing only the extra benefit is that OP can do so at any time.
Although
I could have used this, I think it's a bad idea. I barely go back to read updates in the first post(s). Forum users read new posts, so if there's any news to add, add it as a new posts.
For exmaple: In signature campaigns, the manager might tell us about new openings, OR in some big threads like those of MERIT history, Bitcointalk updates where big debates are going on, some good announcements to be made etc etc.
You can edit the OP with the latest additions, and quote that part as a new post to bring it to the attention of existing readers.
Yes, we don't go to the first post but when we reach the updates late, you have to find the new update in the newly added pages. The same thing which I said for above reply.
In your quoted link if you had UP button option then your list could have been continued to previous one! Easy track.
Of course I can quote, but it will be lost in the new pages.
For example;
See how people are behaving in this campaign thread, and how others are making efforts to tell new people that there had been an update which they should follow!!
OP's NEW UPDATEPEOPLE telling OTHER PEOPLE to CHECK UPDATE
The UP button as you can imagine one can move the post upwards and bring it to the top of rest OR just below the original post.
Who?
Only the original poster will have this option available. Since in his thread he is the updater we concerned about.
There are many other threads, sections where this can be useful function.
I just imagine the idea of having a pinned post then I come up with this kind of idea that the OP can transfer on the top the thread.
This could be good idea as well. But for keeping layout to the current form just a small UP button would do most of the work.
So this idea could get 50/50 marks.
In some instances as LoyceV said they barely go to first page to check the updates. But lets think about mega threads like old campaigns, bounties, and debate threads there it can be helpful.
Also once everyone knows about this option then they will surely check the first page. It would take few days but everyone will get hands on it.