What's up with the following pair of sentences?

1. The Smiths are selling their furniture.
2. The plants are selling like hotcakes.

• #1 is obviously a standard present progressive SVO.  Is #2 just an intransitive form of "to sell"? 
  
• Are there other examples like this or is this idiosyncratic to "sell"?

Just thought of another possible candidate:

• John is growing cauliflower.
• The cauliflower is growing bigger every day.

Thanks,

John