Same here. I've been using "todo.txt" for years (decade?) now. It's hardly more than a very loosely defined format to present TODOs. Lot's of tools, apps, GUIs and whatnot developed around it.
The format is so easy that anything that can edit txt allows to manage it without hassle, so even if MyFavoriteTool is abandoned in a year, I can continue with my todo system. And synching a text file is a no-brainer too. I now just use dropbox. But used git, rsync and some more in the past.
The only downside I've constantly run against, is that I cannot "share" this with my spouse or colleagues. Guess "team" function could easily be invented, but so far no one has, that I know, and I'm not going to put that task on this todo.txt file either.
I think i read some where (or maybe i heard it on a podcast?) about a user of todo.txt who maintained a separate todo.txt like shared-todos.txt or something which basically was a file which was shared with others to track , well, shared tasks. I think they also incorporated a shared calendar, but can't recall if the calendar and the shared text file were connected manually or automatically (through some bash script). I don't recall any more of the details. But, i guess it is possible, and at least one person does employ this tactic. My assumption there is that any sharing of such a text file would necesitate that all collaborators are text file-centric users too.
This approach is not something that would work for my family...but, maybe i have a friend or 2 (at most!) who could collaborate this way (that is, sharing a text file of ToDos). But, i wonder how annoying it would be to track such a separete file for this? Hmmm. I think at some point the need for multi-person collaboration might break down with only a single text file...and since things likely need to get at least a little more sophisticated, might necesitate more tooling. I guess.
The format is so easy that anything that can edit txt allows to manage it without hassle, so even if MyFavoriteTool is abandoned in a year, I can continue with my todo system. And synching a text file is a no-brainer too. I now just use dropbox. But used git, rsync and some more in the past.
The only downside I've constantly run against, is that I cannot "share" this with my spouse or colleagues. Guess "team" function could easily be invented, but so far no one has, that I know, and I'm not going to put that task on this todo.txt file either.