Blackshaw's solicitor said his 21-year-old client and his family were "somewhat shocked by the sentence".
The judge said on Tuesday he hoped the sentences would act as a deterrent.
He also praised the swift actions of the police.
Blackshaw and Sutcliffe-Keenan pleaded guilty under sections 44 and 46 of the Serious Crime Act to intentionally encouraging another to assist the commission of an indictable offence.
The Liberal Democrat peer, Lord Carlile, president of the Howard League for Penal Reform, said he was "surprised" by the sentences.
'Started as a joke' He added: "The Chester sentence was handed out by a very experienced and highly regarded judge who was reflecting the views of the community he serves.
"But the sentences are heavy, and there are no guideline cases for judges to work from for this situation.
"I would expect the court of appeal to be asked very soon to provide a guideline case or cases so that judges can provide consistent, if severe, sentences around the country."
The page said people should meet on 9 August, between 13:00 and 16:00 BST, "behind maccies" - thought to be McDonald's in Northwich town centre.
Chris Johnson, of Moss Haselhurst solicitors in Winsford, said: "It was something which was started as a joke by Jordan.
"Obviously it was rather misplaced and misguided.
"We are not aware of anyone taking up the call that they made.
"Northwich, as far as we understand, has remained peaceful."
'Over the top' There has been criticism from MPs, barristers and campaigners that the sentences handed down to some of those involved in riots across England have been too severe.
Liberal Democrat MP Tom Brake said sentences "should be about restorative justice", not retribution, while Labour MP Paul Flynn said the government was "throwing away sentencing rules".
And leading criminal barrister John Cooper QC said he believed some sentences were "over the top" and likely to be overturned by the Court of Appeal.
But Communities Secretary Eric Pickles has said "exemplary sentences" are necessary and that people need to understand the consequences of rioting, looting and disorder.