Thread-jacking is the practice of appending your question to an existing thread in a forum or news group. This is a relatively common practice among newcomers, and while you obviously weren't to know, it is discouraged. People thread-jack for two main reasons:
- First, you may feel that your question is similar to the one that was asked in the initial post (or OP for original post).
- Second, you may want to reference something in the thread to highlight a problem you are having, such as "I tried this approach, but can't get it to work".
Chances are that you found the thread as a result of using the Forum's search facility or Google, which is an excellent start to getting your problem resolved. However, if your question is the same and the thread is current, then you should wait until the thread is resolved at which point you should get the answer to your problem. If your question isn't answered by the end of the thread, then it must be a different question, and therefore should require a new thread of its own. If you want to reference an old thread or post, then start a new thread and post a link to the thread that contains the solution you are trying to implement.
Adding your question to a current thread might be considered very rude. It's a bit like walking in on someone else's conversation and shouting "What about me?". If anyone answers your question the thread is likely to get very confused, and no one will be quite sure who is addressing which problem. Try following this thread which illustrates the problem pretty well.
Resurrecting an old resolved thread (necroposting) reduces your chances of obtaining help. A lot of people who provide help are watching for unresolved posts, and will ignore a resolved one that has suddenly come to life again. Also, a lot of answerers at forums.asp.net are "points-conscious", in that if their reply to a thread is "Marked As Answer", they are awarded extra points. However, only the person who started the thread has the facility to mark posts as answer. Since you didn't start the thread, there is no motivation among this group of answerers to help you, because you can't Mark As Answer on someone else's thread.
Thread-jacking might also be seen as a way of avoiding the delays that sometimes occur while a post is being moderated for approval. This can be frowned upon too.
So, start a new thread. But before doing so, consider the following general guidance:
- Google first. The vast majority of question posted to forums and newsgroups have already been asked and answered. You may save a lot of time by searching. I find this works particularly well if you Google your error message.
- If your question is of a general nature: "How do I use HttpWebRequest/SqlDataSource/GridView/ASP.NET Membership...*" try reading some tutorials first.
- Provide a meaningful title to the post. "Help ME!!!" is not meaningful. "URGENT!!!" suggests you are late with your homework.
- Make the title relevant to the problem. "Ajax Problem" followed by a description of the failure to update a database will get the wrong people looking at your post.
- Be specific. Don't just say your code "Doesn't work" or "is broke" . Explain what you are trying to achieve. What steps did you take? What happened? What have you already tried to resolve the problem?
- Avoid using SMS style abbreviations in your post. Many of us are too old to be bothered trying to deciphering it.
- Please DO NOT start your post with the word "So", as in "So I built this app...." **
- Don't give a detailed overview of the purpose of your application. It is rarely relevant to your problem.
- Show the relevant code and error message if appropriate.
- Paste the actual code you are using - not a typo-ridden syntactically-rubbish "something that looks like it"
- Reference relevant material or threads if appropriate by providing links.
- If you really have to use an image as part of your post, use the Preview tab to make sure the link works.
- Say which language you prefer, if not obvious from your code.
- Say which database type and version you are using, if your question is database-related.
- Don't apologise for being new to anything. Everyone was once.
- Read what you have written before submitting your post. If English is your first language, and you haven't taken the trouble to ensure that your post makes sense, no one is going to spend time trying to make sense of it for you.
 "Relevant" code means sufficient to see the line that produced the error in context, or enough for people to create a sample page to test themselves. 792 lines of aspx mostly composed of styling information is enough to put anyone off reading your post.
Speaking of styling, if you don't know how to use external CSS files yet, you really are better off getting your page working properly before spending hours fiddling around with the Properties panel to format your various controls, especially if the result of the error you get means you have to replace controls, or the page entirely.
*Delete as appropriate
**Ok, so that's a personal bugbear of mine :-)