[OSM-newbies] Trust Yahoo or OSM?

[Mike N.]

> the top of the help screen, click on the word "Surveying". The last
> paragraph under "Using Satellite Photos" describes the process for
> shifting the photos against the map.

   Once the photos have been aligned, does the alignment apply to my future 
sessions?

   Does the alignment apply to others' future edit sessions?

   Are any photos 'distorted' (in rural areas for example), where I might 
align the area where I'm editing, but mis-align another area outside the 
edit area?

 Thanks,