Topic drift occurs when the subject of an online discussion departs from the topic raised in the original post.
Have you ever read through or participated in an online discussion that was initially started to discuss one subject, but eventually led to a discussion about a completely unrelated topic? What you have witnessed is called topic drift, and it is a common phenomenon in online discussions.
In practice, the term is also frequently used as a gentle reminder to return to the original topic of conversation: “The original post asked about the difference between diesel and gasoline engines, but now we're talking about whether or not it's ok to overnight at rest areas during a long road trip. Talk about topic drift! Interesting conversation but let's try to focus on answering the original question.”
Two concepts that are closely related to topic drift are digression and fragmentation.
Digression occurs when a section of a speech or literary work veers away from the primary topic to an apparently unrelated topic. In planned speeches and literature, digression often occurs intentionally as a way to hold interest and illustrate a concept. For example, a speech might open with a seemingly random story which is later shown to illustrate one of the key concepts at the center of the speech. When digression occurs in an informal conversation the phrase “but I digress” is often used to key that the conversation should return to the original topic.
Fragmentation takes place when multiple subjects are discussed concurrently in a threaded discussion. Fragmentation is easiest understood by way of example:
- Original post asks a question about topic “A”
- First reply addresses topic “A” and brings up topic “B”
- Second reply addresses topic “A” and brings up topic “C” but ignores topic “B”
- Third reply addresses topic “C” and ignores all other topics
- Fourth reply addresses topic “C” and topic “B” but ignores topic “A”
- Fifth reply addresses topic “A” and brings up topic “D” but ignores topics “B” and “C”
In this example, by the time the fifth reply is posted, the conversation has fragmented into four distinct topics which are all being addressed in a single threaded discussion.
Also See: Thread
Frequently Asked Questions
Should topic drift be avoided?
In private conversations, such as an e-mail chain between two people, topic drift is perfectly acceptable. However, in public communications, such as forum discussions, it is important to address new topics with a new post. This is important for at least two reasons.
- First, injecting a new topic into a threaded conversation may hijack the conversation and take it in a new direction leaving the original question unanswered, thereby reducing the usefulness of the conversation to the person who made the original post.
- Second, users who search a public forum for information often depend on the subject identified in the original post to locate relevant information. As a result, public threaded discussions are most useful when they reflect the topic mentioned in the original post, and a new discussion thread should be started to discuss new topics.
How do public forums avoid topic drift?
Some public forums exist to create a database of useful information. Stack Overflow is a good example of this type of forum. Since Stack Overflow is designed to be a repository of technical knowledge in Questions & Answer format, it's important that conversations stay on-topic and are easy for users to find. In order to avoid topic drift, sites like this have very clear guidelines about avoiding topic drift that users must agree to before posting, and enable moderators to close a conversation to further replies once the key question has been answered.