There is a rumour about hard fork of ETH and the volume in the trading of ETH is aggressively growing .Prices are showing strength .Is it an opportunity to buy on rumour and sell on the news to book profit.
That is very true. Most people who had cheap eth sold when it was around 500-1000$ and never regretted doing so. This is the right time to buy and when things are good, you sell for new people at a higher cost.
They were selling ethereum because they are waiting for a long time to see the price increase back. And now, they can see this is happening, so they decide to sell ethereum. I think right now is a good time to sell some portion if we were bought ethereum at the low price so we can get the profit. But if we buy ethereum at $100-$130, then I think you need to wait for another time to see the higher price so you can make a bigger profit.