This page contains information for many aspects of philatelic activity.
You will find a list of websites that will direct you to a variety of resources to support your collecting activities
https://www.theswedishtiger.com/
The Swedish Tiger is a website that provides detailed information on all US regular issues and commemorative stamps from 1847 to 1939.In addition, it provides the same information for all US air mail stamps. This information includes pictures all stamps, their Scott numbers, and for classic US stamps, detailed information about the stamp and all its variations (how to identify the stamp).
The Stamp Albums website offers the opportunity to download unlimited amounts of stamp album pages from any country in the world from their earliest stamp issues to the current year. A year's subscription to this site is $75.00. If you collect world wide stamps, this site offers an excellent value, compared to buying individual specialized albums for each country. I can personally endorse this site.
This is the website for the American Philatelic Society, the largest US organization for stamp collecting. It is a non-profit organization that offers services for collectors, educators, and postal historians. It offers a variety of services to the stamp collecting community.
The Stamp world website offers the largest online collection of FREE world-wide stamp catalogs as well as selection of other services.
https://www.americanairmailsociety.org/
The American Air Mail Society (AAMS), founded in 1923, is a volunteer-driven, organization for collectors passionate about the study, preservation and communication of information regarding aerophilately —stamps, covers, and postal history. The AAMS is a 501(c)(3) non-profit charitable organization.
https://www.americantopical.org/
The American Topical Association is devoted to stamp collectors who choose to collect stamps on particular topic such as flowers, trains, castles, cats, flags, presidents, musicians, artists, athletes. Other topics might be stamps that commemorate a particular event or person. There are specific groups within the ATA that focus on just one topic.
The United Postal Stationary Society hosts collectors who focus on various types of postal stationary such as postal cards, stamped envelopes, embossed envelopes, wrappers, and areographs. One of the main divisions of the UPSS is postal history where collectors study postmarks and postal markings to chart the history of events and people.