My toilet started gurgling/bubbling. I went to check it out and found soap bubbles in the toilet!

Our home is 8 yrs old, with 3 toilets. There three of us living here. We had the septic tank cleaned out 2 yrs ago. The gentleman that did the work, made the comment - "You were probably a week away form it backing up into the house." We have called him and he will be here tomorrow afternoon. Is there anything we should know or consider in this situation?

Thank you for any help on this.