Excel Tactics is just one of many great resources online for learning Excel techniques and getting questions answered. These are a few of my favorites.

 

Online Courses and Tutorials

Excel Exposure
Created and maintained by cobainbc15 of Reddit. Structured video courses on basic Excel concepts. Part of Reddit’s University of Reddit course offering.

Chandoo
“Become Awesome at Excel.” Excel how-to blog with weekly tip posts.

Excel Central
Structured video lessons for basic to intermediate Excel skills.

 

Forums, Message Boards, and Q&A Sites

MrExcel Forum
The most active message board for Excel questions on the Internet. Post your clearly worded questions here, and you’ll get excellent and speedy help from volunteer experts.

Reddit /r/Excel
Excel has its very own sub-reddit. More speedy answers from pros. Be nice, reward good answers with upvotes, and provide detailed questions to get answers quickly.

ExcelForum.com
Another high-traffic message board with a sub-board for Basic questions. This one allows spreadsheet attachments if your questions are specific or complex.

Stack Overflow
Excel tag on the questions and answers coding site. Special tags for excel-vba, excel-formulas, and specific versions of the application.

 

Advanced Resources

OZGrid Excel VBA Archive
Over 150 pre-made VBA and Macro-based solutions to common Excel scenarios.