[tomsem]

How big is your "My Clippings" file? the bigger it gets, the slower it will be to add notes. There are two reasons: 1) Kindle does not keep the file open, each time you add a note, it has to start at the beginning and seek for the end of file before it can append the new note. The seek will take slightly longer and longer as the file grows. 2) whenever you add a note, Kindle has to index the 'my clippings' file again. Kindle cannot modify 'my clippings' until indexing is finished, as this requires exclusive, write access. Again, the larger the 'my clippings' file, the longer it takes to index the file after each note is added, and the longer the wait for write access.

The 'randomness' is due to the fact that sometimes it has finished indexing by the time you add the next note, and sometimes it has not.

The solution is to periodically backup your existing clippings file (whenever it starts feeling slow) and start a new one. You could even just rename 'My Clippings.txt' (e.g to 'My Clippings 20110517.txt') and still be able to read it on Kindle as a text file. Kindle will create a new 'My Clippings.txt' to hold all subsequent notes you make.

I can think of several ways Amazon could address this issue, but they all have drawbacks. For example, they could automatically 'archive' My Clippings when it got to a certain size (again, renaming the existing file and starting a new one). But then when one wanted to extract something to use on the computer, you'd have several files to look through instead of just the one.

Or (my favorite) they could get rid of My Clippings (and thus its 'overhead' in terms of processor and storage) altogether and add an 'Export notes and highlights' option to each item. However they'd also need to figure out how to index your notes and highlights (as stored in the binary sidecar files) so they could still show up in search results. (hmm and will they ever bother to index PDF files so they can show up in search results?)

Amazon usually seems to favor brain-dead simplicity whenever the alternative is to add additional UI and 'options'. The only thing that might influence them is the cost of support calls generated by people calling with this particular performance issue. Since most Kindle users are not copious note-takers (I assume) this is probably not an issue for them, however.