Web services can be several things from tools related to communication without a web platform to services usually related to web sites and includes many services offered to web masters, such as Web Hosting, search engine submission, site up-time reports and much more.
Even search engines provide a 'web service' by providing suggestions for a search terms , known generally as "keywords", to it's users.
"Yes! Picasa provides a free web album service, which is open to the public for your convenient use anytime, anywhere. You never have to pay a cent to use them."
Mail to Web is a service that allows for the collection of email over the web. It is useful when it would ordinarily be necessary to use a service like Outlook to access email.
Customer service, use of technology, and strengths and limitations are all things to consider.
When I am on my friends computer I can't use my e-mail program. Is it secure to use the login of the web-based e-mail service at the Earthlink website?
CenturyTel web mail offer an easy to use email service that can be accessed from anywhere since it's a webmail service. The service can be accessed by using the URL adress in any browser.
A "callback URL" is the web address an API needs to send information for use in a different web site.For example, a web developer is building a web application for use in conjunction with another web service's API (such as Facebook or Last.fm). The application is hosted on the web developer's server, and the other web service stores the callback URL so that it knows where to send information when it is requested by the developer's application.http://www.encomsolution.com
Use a VPN - either configure your own VPN endpoints or use a commercial third party service to connect your system to the web in a secure fashion.
This web site: www.whitepages.com/reverse_phone provides a pretty popular service that a lot of people use.
A "callback URL" is the web address an API needs to send information for use in a different web site. For example, a web developer is building a web application for use in conjunction with another web service's API (such as Facebook or Last.fm). The application is hosted on the web developer's server, and the other web service stores the callback URL so that it knows where to send information when it is requested by the developer's application. See Also: http://en.wikipedia.org/wiki/Callback_(computer_science)
WizCat is not web service indipent, It use Online Public Access control to access the library for people to search.
You can use the search facility to find people that might be interested in your service. You can search for key words.
You can learn anything for free on the web. It is used as online home school and online college everyday by millions of people.