I have a question for reddit users. Why don't my submissions show up on the New page? Is there some sort of filter or time frame when posts are shown?
They do have a spam filter designed to detect spam posts. However, legit posts can also be caught by the filter. If minutes go by and your post isn't showing up, it has probably been caught by the filter. This is most likely to occur if you post to a subreddit that you have not participated in before.
Be descriptive and don't be too aggressive in posting your title. Phrases like, "Vote this to spread the word!" or "AMAZING!" tend to annoy most redditors which increases the chances of your post being marked as spam.