Are On Line Tools Safe to Check Stats

The answer is not really.

Google and other search engines do not like being bombarded by on line tools that do not serve their basic purpose, search. It is a violation of their terms of service.

Some tools do not send your domain name when performing their task. Some do.

If a tool stores information about your domain that information can be mined in the future or even sold to others.

Few tools store data, but a few quite useful ones do.

Caution is necessary if you use on line tools.