Just finished a mission I set myself to clean out the UK Tagwatch (http://tagwatch.stoecker.eu) a bit. Don't panic though, I haven't been bulldozing away all the new and novel tags people are using, just going through it all carefully with a duster and having a go at the following:

*Fixing spelling mistakes. By the nature of Tagwatch, this mainly means spelling mistakes in the tags, not the values. For example, I'll definitely have caught amneity=parking, but not necessarily amenity=praking. Also I might have left a tag or two that was obviously only being used by one person as *all* instances were misspelled. ;-) This category included trailing spaces, although I think a lot of these get auto-fixed eventually even if I don't bother...

*Nonstandard -> standard tags. This was by far the biggest job, as these are trickier to spot by users outside of Tagwatch. Let's face it, we don't all remember the entire Map Features page all the time, and so sometimes we put max_speed instead of maxspeed, or think the tag for phone numbers is "telephone=" instead of "phone=". I know I do, since I've embarrassed myself by turning up plenty of my own mistakes like these as I've gone through...! Unfortunately some of the most common mistakes were made just too often to be fixed by hand by me in any sensible time: if anyone feels like finishing off "telephone=*" then go ahead, but you're in for a long job!

*Nonstandard -> nonstandard (i.e. unapproved) tags. This is the main controversial bit - I've tried to be as careful about it as I can, and I hope I haven't stood on anybody's toes too much while doing it. If I have - please do change back whatever you're annoyed about, or tell me to do it, or ask why I've done it (as a few people here and there have done already). My standard answer is that tags representing the same thing should be the same (and their exact wordings can be changed around later), so if I'm confident that Tag 1 means the same as well-used Tag 2 (and there aren't too many examples of Tag 1 to do this carefully on a case-by-case basis) then I've grouped them all under Tag 2, even if that tag doesn't have formal approval yet. Note that I'm not saying Tag 2 is good or Tag 1 is rubbish - just that there were very few examples of Tag 1 compared to lots of Tag 2. For example, one of the last things I did was take the "uk:row" tag (short for uk:right-of-way, I discovered) and merge it into the "designation" tag where all its values had corresponding values. It doesn't matter to me whether designation gets approved or replaced with something else - all I'm trying to do is make it so when the dust settles, you know where to search for the relevant nodes, ways and relations to start the conversion process.

*Grouping very minor tags. Some of these edits were a bit cheeky, but they're for the same kind of reasons as the set above. Consider them as no more than suggestions for tags you might like to use to represent a common concept...

So I know that this autumn-clean is going to be undone the very day I stop monitoring Tagwatch... but hopefully it's come in at least a bit useful and saved someone a bit of time down the line! I think I'll probably have another OSM break now though...

SbU